Expose changes in the network quality to the renderers

content/browser/net/network_quality_observer_impl.h

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CONTENT_BROWSER_NET_NETWORK_QUALITY_OBSERVER_IMPL_H_
+#define CONTENT_BROWSER_NET_NETWORK_QUALITY_OBSERVER_IMPL_H_
+
+#include <stdint.h>
+
+#include <memory>
+
+#include "base/macros.h"
+#include "base/threading/thread_checker.h"
+#include "content/common/content_export.h"
+#include "content/public/browser/network_quality_observer_factory.h"
+#include "net/nqe/network_quality.h"
+#include "net/nqe/network_quality_estimator.h"
+
+namespace content {
+
+// Listens for changes to the network quality and manages sending updates to
+// each RenderProcess via mojo.
+class CONTENT_EXPORT NetworkQualityObserverImpl
+    : public net::NetworkQualityEstimator::RTTAndThroughputEstimatesObserver {
+ public:
+  explicit NetworkQualityObserverImpl(
+      net::NetworkQualityEstimator* network_quality_estimator);
+
+  ~NetworkQualityObserverImpl() override;
+
+ private:
+  class UiThreadObserver;
+
+  // net::NetworkQualityEstimator::RTTAndThroughputEstimatesObserver
+  // implementation:
+  void OnRTTOrThroughputEstimatesComputed(
+      base::TimeDelta http_rtt,
+      base::TimeDelta transport_rtt,
+      int32_t downstream_throughput_kbps) override;
+
+  // |ui_thread_observer_| is owned by |this|, and interacts with
+  // the render processes. It is created on the IO thread but afterwards, should
+  // only be accessed on the UI thread.
+  std::unique_ptr<UiThreadObserver> ui_thread_observer_;
+
+  // |network_quality_estimator_| is guaranteed to be non-null during the
+  // lifetime of |this|.
+  net::NetworkQualityEstimator* network_quality_estimator_;
+
+  //  The network quality when the |ui_thread_observer_| was last notified.
+  net::nqe::internal::NetworkQuality last_notified_network_quality_;
+
+  base::ThreadChecker thread_checker_;
+
+  DISALLOW_COPY_AND_ASSIGN(NetworkQualityObserverImpl);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_NET_NETWORK_QUALITY_OBSERVER_IMPL_H_